Solubilization of a homopolymer in a block copolymer

Journal Article · Mon Apr 25 04:00:00 EDT 1994 · Macromolecules; (United States)

DOI:https://doi.org/10.1021/ma00087a012· OSTI ID:7198171

Jeon, K J; Roe, R J ^[1]

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1. Univ. of Cincinnati, OH (United States). Dept of Materials Science and Engineering

Blends containing styrene-butadiene diblock copolymer (50 wt % styrene content) and polystyrene of various molecular weights are studied by light scattering, transmission electron microscopy, and small-angle X-ray scattering. The solubility of polystyrene in the styrene domain of the block copolymer is governed by the ratio of the homopolymer molecular weight to the block molecular weight. A finite solubility limit exists when this ratio exceeds [approximately]1. The lamellar repeat period increases linearly as more polystyrene is added, but the butadiene layer thickness remains constant, signifying that the average interfacial area occupied by a copolymer junction point does not change with added polystyrene. This contrasts to the case found by the others that the average area per junction point increases when the added homopolymer is smaller than the block size. Small-angle X-ray scattering patterns obtained from samples having lamellar morphology are described by an idealized model in which layers of styrene and butadiene of randomly varying thicknesses with a diffuse interface between them are stacked parallel.

• OSTI ID: 7198171
• Journal Information: Macromolecules; (United States), Journal Name: Macromolecules; (United States) Vol. 27:9; ISSN MAMOBX; ISSN 0024-9297
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
COPOLYMERS
MATERIALS
MATHEMATICAL MODELS
MORPHOLOGY
ORGANIC COMPOUNDS
ORGANIC POLYMERS
PETROCHEMICALS
PETROLEUM PRODUCTS
PLASTICS
POLYMERS
POLYOLEFINS
POLYSTYRENE
POLYVINYLS
SOLUBILITY
SOLVENT PROPERTIES
SYNTHETIC MATERIALS